The present disclosure relates to a distractor for distracting bone surfaces, particularly, of a mandible. Distraction is a commonly applied surgical procedure in various patient regions. For example, airway obstruction due to micrognathia is a frequent complication in infants and young children with congenital craniofacial syndromes such as Nager syndrome, Treacher Collins syndrome, and Goldenhar syndrome. These syndromes, along with specific secondary conditions such as maxillary hypoplasia in the setting of cleft lip and palate, hemifacial, microsomia, and Pierre Robin sequence, may require some sort of mandibular distraction. The small mandible can causes prolapse of the tongue base against the posterior pharyngeal wall leading to respiratory distress. Particularly in young infants, airway obstruction is also commonly associated with feeding difficulties resulting in failure to thrive.
Mandibular distraction osteogenesis using an implanted distractor provides an alternative to traditional methods of airway management in infants with Pierre Robin Sequence. This approach consists of lengthening of the mandible, which allows the tongue base to move forward by its anterior muscular attachments to the mandible. Furthermore, this approach has allowed avoidance of tracheostomy as well as early decanulation in infants with Pierre Robin sequence. Tracheostomy in neonates is associated with perioperative and postoperative morbidity such as hemorrhage, pneumothorax, and tracheal stenosis.
U.S. Pat. No. 8,287,573 discloses a mandibular distractor with a one-directional ratchet mechanism. After distraction, reverse distraction is not possible. U.S. Pat. No. 7,875,033 discloses a bone distractor comprising a locking screw for locking a distracted position in place. The locking screw must be unlocked for further distraction to be possible. U.S. Pat. No. 6,277,124 discloses a bone footplate with a one-way ratchet mechanism. U.S. Patent Publication No. 2014/0148812 relates to a pediatric internal mandibular distractor, the disclosure of which is incorporated herein by reference.
It has been found that the prior art distractors cannot always be adequately adjusted in their implanted state.